Dr. Universe: Why does the wind blow? -Odin, 7, Mt. Vernon, Wash.

When the wind blows, it can do all kinds of things. It can help pick up tiny seeds and carry them away, so plants and flowers can grow in new places. It can push a big sailboat across an ocean. We can even harness the wind to make clean energy to power our homes and schools.

That’s what I found out from my friend Gordon Taub, an engineer at Washington State University. He is very curious about wind energy and told me more about why the wind blows.

Whether it’s a breeze, a gust, or a gale, winds are blowing in our atmosphere all the time. When the sun heats the earth, it doesn’t actually heat the earth evenly.

Part of the reason the Earth doesn’t heat up evenly is because it is tilted at an angle toward the sun. That means the sun’s rays hit most directly and intensely at the Earth’s equator. Earth is a sphere, so the sun’s rays spread out over a wider area closer to the poles. Where the rays hit directly, the air is warmer; where they reach Earth at more of an angle, the air is cooler. The Earth is also full of different kinds of surfaces that heat and cool at different rates – mountains and valleys, areas with and without water.

This means there are pockets of warmer and cooler air all over the Earth. Winds arise when cool and warm air meet.

When the air at the equator warms up, it expands, Gordon reminded me. Things start cycling around as cooler, high-pressure air moves in to places where there is warmer, low-pressure air. This mixing and movement of air at different temperatures and pressures is what gives us our winds.

The wind holds a lot of energy, too. Wind turbines can help take the kinetic or motion energy of wind and turn it into electrical energy that can power our world.

Taub’s students are actually working on a wind turbine project of their own this year and will debut it at a national competition in 2020. If you are curious about wind, maybe one day you’ll join students at WSU to investigate wind power, too.

Maybe you’ve also seen some wind turbines if you’ve traveled across our state. Taub said wind turbines usually start spinning when the wind is blowing about 11 m.p.h. They usually shut down when winds reach speeds of about 44 m.p.h., so the blades don’t get busted up.

You know, we have some pretty strong winds on planet Earth: for example, winds of over 230 mph on Mt. Washington in New Hampshire. But that’s nothing compared to other planets. Neptune’s winds are the fastest in the solar system, reaching 1,600 mph—even faster than a fighter jet.

On earth, wind can also help us stay cool on hot days. I think I’m going to make my very own wind-powered pinwheel this summer. You can try to make one of your own, too. We’ll need some scissors, paper, a wooden stick, and a brass fastener. Find all the instructions here and then watch your creation spin in the wind.

Sincerely,

Dr. Universe

Note: This post has been edited for clarity and accuracy on January 21, 2020. Thank you to Dr. Eric Russell, Asst. Research Professor in WSU’s Dept. of Civil and Environmental Engineering, for the additional information on wind formation.